Improvement in air-vacuum engines



2 Seets--Sheet 2.

fA. K. mman. 'Air-Vacuum Engines.

`menm 1an. 5, 1375.`

Noxa-8,525'.

THE GRAPHIC CDAPHDTD-LITH3931 44 PARK PL^CE,N,Y.

UNITED STATES PATENT OEEIoEo ALEXANDER K. RIDER, OF VVALDEN, NEW YORK,ASSIGNOR TO RIDER, WOOSTER & OO., OF SAME PLACE.

IMPROVEMENT IN AIR-VACUUM ENGINES.

Specification forming part-of Letters Patent No.158,525, dated January5, 1875; application tiled May 20, 1874.

To all whom it may concern:

Be it known that I, A. K. RIDER, of Walden, Orange county, in the Stateof New York, have invented an Improvement in Air-Engines, which may betermed an Air-Vacuum Engine, of which the following is a specication:

This engine is operated by a partial vacuum produced by cooling hot air.It has two cylinders, and transfers the air from one to the other,passing it through a cooler in transit. It receives the air hot anddischarges it comparatively cold. As usually constructed, the enginereceivesthe air at the pressure of the atmosphere and discharges it atthe same pressure 5 but it may be made to work under an articialatmosphere of more than normal density, if preferred, by using tightcovers on the two cylinders and exhausting into a receiver.

The engine, in general construction, is composed essentially of aworking'cylin der, acooler or condenser, and an airpump, with suitablevalves and controlling means. The inlet and outlet valves of the maincylinder are operated by cams or eccentrics; but the valves of the pumpoperate automatically by dii'erence of pressure, as usual.

The cooler or condenser O is arranged between the main cylinder A andthe pump B. It is shown in the drawing as a double cylindrical vesselimmersed in water, and having a cylindrical diaphragm in the interior togive greater length of current to the air being cooled. Other forms ofcondenser may be used, but not as well. The cranks are arranged in sucha manner that the pump upstroke begins before the piston of the maincylinder has completed its upstroke by about one-sixth of the stroke;The cranks are set about one hundred and thirty degrees apart. The maincylinder A takes its supply of heated air direct from the furnace orother source of heat, and the inlet-valve of the main cylinder closesconsiderably before the completion of the upstroke, thus expanding theinclosed hot air in the main cylinder to any desirable point, and theexpansion is subsequently carried still farther by the pump commencingto draw soon after the closure of the inlet-valve, which per mits thework of exhaustion in the pump to be performed, in a great measure,before any considerable portion of the air is cqoled. rlhe stroke ofthepump is, therefore, accomplished with much less power than would berequired if the strokes of main piston. and pump were simultaneous andopposite each other; or, in other terms, the expansion of the heated airis carried out much farther with corresponding gain. The character andamount of this gain are shown by diagrams on Sheet 2 of the drawings,marked l, 2, 3, and 4.

The power is derived from the unbalanced pressure of the atmosphereacting rst on the piston a of the main cylinder A, and afterward on thepiston b ofthe pump B. The inlet and outlet valves of the main cylinderare so operated by cams on the main shaft that one is closed before theother opens. The inlet-valve should be open at the moment the mainpiston begins its upstroke, and may shut at any point in the stroke lessthan iive-` eighths of the whole stroke upward, according to therequired degree of expansion. The outlet-valve of main cylinder shouldopen at the commencement of the upstroke of the pump. The inlet-valveopens outward and the outlet inward.

In engines designed for pumping, the water being pumped is carriedthrough the coolingchamber surrounding the condenser,'saidcooling-chamber being simply a part of the suction or discharge pipe ofthe pump. This en'- gine may take the hot air from the chimney of anyordinary iire or range, as when used for a household pumping-engine. Inthat case a special ire to operate the engine is dispensed with; or itmay be run with gas-burners, arranged in a proper combustion-chamber; orit may have the air heated in a heater specially constructed, similar tothat in my air-engine patented July 16, 1872; reissued March 25, 1873.

Other constructions of cylinder and pump will serve, with some success,the purpose intended by this arrangement, provided that the main pistonbegins its upstroke before the former has completed its upstroke,whether it is by cross-connection or separate motion, or by beams orlevers.

Sheet 2 represents diagrams as produced by the Well-known instrumenttermed the indicator. Diagram 1 represents cards from the main cylinderA and from the pump B, superposed. The cranks are arranged, as hereindescribed, one hundred and thirty degrees apart. The effective meanpressure in the cylinder, allowing nothing for leakage or friction, issix and one-half pounds per square inch. Diagram 3 shows the theoreticalcards superposed, Which would be taken from the main cylinder and pumpif the cranks Were in the same plane, so that the main piston and thepump-piston rose and sank exactly simultaneously.

The effective mean pressure so arranged, allowing nothing for leakage orfriction, would be only four and three-tenths pounds per square inch.

The exhaustive pump B, combined with the v

